Optical disc driving device

ABSTRACT

An optical disc driving device having a metallic exterior casing composed of a first casing and a second casing and an internal unit to be housed in the exterior casing, the internal unit including an optical pickup unit having an optical pickup part that moves in radial directions of an optical disc to perform recording or reproduction of information signals on the optical disc, wherein at a portion, which the optical pickup part moved radially outward of the optical disc makes a closest approach to, in either one of the first casing or the second casing opposed to the first casting, a protrusion for electrically connecting the first casing and the second casing to each other is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of International Application No. PCT/JP2012/000183, with an international filing date of Jan. 13, 2012, which claims priority of Japanese Patent Application NO: 2011-031596 filed on Feb. 17, 2011, the content of which is incorporated herein by reference.

BACKGROUND

1. Technical Field

The technical field relates to an optical disc driving device for performing recording or reproduction on an optical disc.

2. Description of Related Art

Conventionally, optical disc drive devices for performing recording or reproduction of information on optical discs such as DVDs and Blu-ray Discs (BDs) are mounted on electronic equipment such as game equipment, recorders and players.

This type of optical disc drive device has an internal unit including an optical pickup unit for performing optical recording or reproduction on an optical disc, a rotation drive device for driving rotation of an optical disc, a moving mechanism for moving the optical pickup unit in radial directions of an optical disc, and the like. Also, the optical disc drive device has an electroconductive, metallic exterior casing for housing the internal unit.

In information recording/reproducing devices such as hard disks, as shown in Japanese Patent Application Publication No. 2001-291985A, conventionally, an internal unit is housed in a metallic exterior casing for purposes of dust prevention for the internal unit and shielding outward radiation noise. Also in optical disc drive devices, the internal unit is housed in a metallic exterior casing from the same reasons.

SUMMARY

In cases where the exterior casing of the optical disc driving device is made up of a plurality of components, there is a need for taking measures against radiation of noise radiated from between the plurality of components to outside.

Accordingly, the present disclosure provides to reduce noise radiated outside from between a plurality of components constituting the exterior casing of the optical disc driving device.

In one general aspect, the present disclosure describes an optical disc driving device having: a metallic exterior casing composed of a first casing and a second casing; and an internal unit to be housed in the exterior casing, the internal unit including an optical pickup unit having an optical pickup part that moves in radial directions of an optical disc to perform recording or reproduction of information signals on the optical disc, wherein at a portion, which the optical pickup part moved radially outward of the optical disc makes a closest approach to, in either one of the first casing or the second casing. opposed to the first casing, a protrusion for electrically connecting the first casing and the second casing to each other is provided.

According to the present disclosure, electrical conduction between the first casing and the second casing, which constitute the exterior casing, can be ensured enough so that release of radiation noise from between the first casing and the second casing to outside can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an appearance of an optical disc drive device according to an embodiment;

FIG. 2 is an exploded perspective view showing a state in which the exterior casing is exploded;

FIG. 3 is a schematic plan view showing a schematic structure of an internal unit of the optical disc drive device;

FIG. 4 is a plan view showing a state in which the internal unit is housed in a first casing;

FIG. 5 is a sectional view showing part of a completed structure in which with the first casing and a second casing set up, the internal unit is housed in the exterior casing;

FIG. 6 is a perspective view showing a positional relationship between the first casing and a printed wiring substrate of a control circuit block;

FIG. 7 is a perspective view showing a state in which the printed wiring substrate is excluded in FIG. 6;

FIG. 8 is a schematic sectional view showing a structure of an interfacing connector portion in the control circuit block; and

FIG. 9 is a schematic view showing a contact state between a fringe portion of an opening of the first casing and a ground pattern of the printed wiring substrate.

DETAILED DESCRIPTION

Hereinbelow, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an appearance of an optical disc drive device according to an embodiment of the disclosure. FIG. 2 is an exploded perspective view showing a state in which the exterior casing is exploded. As shown in FIGS. 1 and 2, the optical disc drive device is made up with an internal unit 2 housed in an electroconductive, metallic exterior casing 1 having a disc insertion opening 1 a. The exterior casing 1 also serves a role as a shield for reducing outward release of radiation noise generated from the internal unit 2.

The exterior casing 1 is composed of a quadrilateral box-like first casing 3, and a quadrilateral lid-like second casing 4 which is put on the first casing 3 so as to cover an upper opening portion of the first casing 3 and which has a front portion 4 a with the disc insertion opening 1 a formed therein. The internal unit 2 can be housed in the exterior casing 1 by first doing temporary fixing, i.e. hanging of the front portion 4 a of the second casing 4 to a front portion of the first casing 3, then putting a rear portion of the second casing 4 on a rear portion of the first casing 3, and subsequently screwing the rear portion of the second casing 4 to the rear portion of the first casing 3 with screws 5.

As shown in FIG. 2, fixing portions 3 a each having a screw hole to which a screw 5 is tightened are provided in the upper opening portion of the first casing 3. At portions of the second casing 4 corresponding to those fixing portions 3 a, through holes 4 b through which the screws 5 are to be inserted are provided, respectively. The screws 5 are inserted through the holes 4 b of the second casing 4, respectively, so as to be tightened to the screw holes of the fixing portions 3 a of the first casing 3.

Further, as shown in FIG. 2, a plurality of fitting portions 3 b each having a screw hole to which a screw is tightened to fix the internal unit 2 into the first casing 3 are formed in a bottom face of the first casing 3.

The exterior casing 1 can be made by molding a sherardized steel sheet having a thickness of 0.4 mm to 0.5 mm. In particular, the first casing 3 can be made by using, for example, thin-plate sheet metal or the like of a copper sheet, tin sheet, stainless sheet or the like having a thickness of 0.2 mm to 0.3 mm. In addition, when rust-proofing property is considered preferentially important, tin plates or stainless sheets are preferably used. In addition, with cost regarded as another important factor, tin plates are preferably used.

FIG. 3 is a schematic plan view showing a schematic structure of the internal unit of the optical disc drive device. As shown in FIG. 3, the internal unit 2 has, in a metallic unit housing 2 a, a spindle motor 6 for holding a center of an optical disc and rotating the disc at high speed, a disc insertion mechanism 7 for guiding an optical disc inserted through the disc insertion opening 1 a to the spindle motor 6, an optical pickup unit 8 for performing recording/reproduction of information signals on an optical disc, and a control circuit block 11 having a printed wiring substrate 10 electrically connected via a flexible wiring substrate 9 to electronic components of the optical pickup unit 8.

The disc insertion mechanism 7, under control by the control circuit block 11, introduces an optical disc inserted through the disc insertion opening 1 a into the internal unit 2 and guides the optical disc to the spindle motor 6 so that the center of the optical disc is aligned with a rotating shaft of the spindle motor 6.

The optical pickup unit 8 has an optical pickup part 8 a on which a semiconductor laser device and an optical lens for applying light of a specified wavelength to an optical disc rotated by the spindle motor 6 are mounted, guide shafts 8 b for holding the optical pickup part 8 a so that the optical pickup part 8 a can be moved linearly in radial directions of the optical disc, and a tracking mechanism for moving the optical pickup part 8 a in radial directions of the optical disc. The tracking mechanism has a gear part 8 c provided in the optical pickup part 8 a, and a rotating shaft 8 d to be meshed with the gear part 8 c. As the rotating shaft 8 d is rotated under control by the control circuit block 11, the optical pickup part 8 a is moved in a radial direction of the optical disc via the gear part 8 c.

The guide shafts 8 b of the optical pickup unit 8 as well as the rotating shaft 8 d of the tracking mechanism are held by holding parts 2 b provided in the unit housing 2 a.

The control circuit block 11 is so made up that a microcomputer or other semiconductor integrated circuit element 11 a and its peripheral circuits are mounted on the printed wiring substrate 10 while an interfacing connector 11 b for transmission and reception of electrical signals from and to external electronic equipment (not shown) is mounted thereon. The semiconductor integrated circuit element 11 a of the control circuit block 11 controls the spindle motor 6, the disc insertion mechanism 7 and the optical pickup unit 8 and moreover processes signals for information writing onto an optical disc via the optical pickup unit 8 or signals read from an optical disc. Signals are also delivered and received between the control circuit block 11 and external electronic equipment via the interfacing connector 11 b.

Further, on the printed wiring substrate 10 of the control circuit block 11, a ground pattern 10 a is formed so as to surround the connector 11 b mounted on the printed wiring substrate 10. Whereas the printed wiring substrate 10 is made up by alternately stacking electrically conductive layers of copper foil or the like and insulating layers of epoxy resin or the like, the ground pattern 10 a can be formed by cutting out part of the insulating layers of the printed wiring substrate 10 so that the conductive layers are exposed.

The ground pattern 10 a, as will be described later, has through holes 10 b formed therein for insertion of screws serving for electrical connection of the ground pattern 10 a and the first casing 3 of the exterior casing 1 to each other as well as for mechanical fitting of the printed wiring substrate 10 to the first casing 3. Further, another ground pattern (not shown) is provided at an end portion of the printed wiring substrate 10. Also provided are through holes 10 c for electrical connection of the exterior casing 1 and the unit housing 2 a to each other via the another ground pattern as well as for mechanical fitting of the printed wiring substrate 10 to the unit housing 2 a (see FIG. 3).

FIG. 4 is a plan view showing a state in which the internal unit is housed in the first casing. As shown in FIG. 4, the internal unit 2 is housed in the first casing 3 so that the printed wiring substrate 10 of the control circuit block 11 is positioned on the bottom side, and the internal unit 2 is fitted to the fitting portions 3 b in the bottom portion of the first casing 3 with screws (not shown). It is noted that as shown in FIG. 4, the internal unit 2 is fitted to the first casing 3 in a state reversed from the state shown in FIG. 3.

FIG. 5 is a sectional view showing part of a completed structure in which with the first casing and the second casing set up, the internal unit is housed in the exterior casing.

As shown in FIGS. 4 and 5, a protrusion 3 c is provided at a portion of the first casing 3 to which the optical pickup part 8 a moved radially outward of the optical disc makes a closest approach, i.e., at a portion of a rear-side side wall fixed with the two screws 5. In this embodiment, the protrusion 3 c is provided, specifically, at a central portion of the side wall of the first casing 3 to which the optical pickup part 8 a makes a closest approach and which corresponds to an intermediate position of the two screws 5.

This protrusion 3 c, which protrudes outward, comes into contact with a side wall 4 c of the second casing 4 when the second casing 4 is fitted to the first casing 3. As a result, the protrusion 3 c and the second casing 4 are electrically connected to each other. The protrusion 3 c is formed by extruding part of the side wall of the first casing 3. Alternatively, the protrusion 3 c may be formed by forming two slits parallel to part of the side wall of the first casing 3 and further bending a portion between the two slits. Furthermore, the protrusion 3 c may also be formed by fitting another metallic member to the side wall of the first casing 3 by welding or brazing or the like. In addition, although FIGS. 4 and 5 show one example in which one protrusion 3 c is formed, a plurality of protrusions 3 c may also be formed in the side wall to which the optical pickup part 8 a makes a closest approach.

Reasons that such a protrusion 3 c is provided are described below. Such an optical disc drive device as shown in FIGS. 1 to 5, in which the internal unit 2 is housed in the exterior casing 1 composed of the first casing 3 and the second casing 4, has been under a demand for downsizing as electronic equipment containing the optical disc drive device gets downsized more and more. For downsizing of the optical disc drive device, such measures are implemented as reduction of clearances between the internal unit 2 and the exterior casing 1, thinning of the exterior casing 1, simplification of the assembling structure of the exterior casing 1, and the like.

However, with the optical disc drive device downsized, it would occur, in some cases, that a central portion of the side wall of the first casing 3 to which the optical pickup part 8 a, when moved to an outermost peripheral portion of an optical disc, makes a closest approach, and/or an opposing central portion of the side wall 4 c of the second casing 4 is flexed. That is, it might occur heretofore that an unfixed portion corresponding to an intermediate position between the two screws 5 is flexed. Moreover, such flexure might cause occurrence of a gap between the side wall of the first casing 3 and the side wall 4 c of the second casing 4.

With occurrence of such a gap, an elongate hole is formed so as to extend from one screw 5 toward the other screw 5, so that electrical conduction between the first casing 3 and the second casing 4 can no longer be secured enough due to the elongate hole. Then, radiation noise becomes more likely to leak from between the side wall of the first casing 3 and the side wall 4 c of the second casing 4, i.e., through the elongate hole.

Accordingly, the protrusion 3 c is provided at a central portion of the rear-side side wall of the first casing 3, to which the optical pickup part 8 a makes a closest approach, as shown in FIGS. 4 and 5, so that even upon the closest approach of the optical pickup part 8 a, the electrical connection between the first casing 3 and the second casing 4 can be maintained. More specifically, the protrusion 3 c is provided in the first casing 3 so that when the second casing 4 is fitted to the first casing 3, the protrusion 3 c presses the side wall 4 c of the second casing toward the outside.

According to the structure having, such a protrusion 3 c as shown above, even with the optical disc drive device provided in a downsized scale, electrical conduction between the portion of the side wall of the first casing 3 to which the optical pickup part 8 a makes a closest approach and the opposing portion of the side wall 4 c of the second casing can be secured enough. As a result, outward release of radiation noise from between the first casing 3 and the second casing 4 can be reduced.

Preferably, as shown in FIG. 3, the optical pickup unit 8 is so placed that the optical pickup part 8 a is moved toward the side wall 4 c opposed to the disc insertion opening 1 a in the same direction as the optical-disc insertion direction. Alternatively, the optical pickup unit 8 may also preferably be so placed that the optical pickup part 8 a is moved in a direction perpendicular to the optical-disc insertion direction. As a result, leakage of radiation noise to the outside through the disc insertion opening 1 a can be suppressed.

Also, the protrusion 3 c may be so formed not that the protrusion 3 c protrudes from a side wall of the first casing 3 so as to come into contact with the side wall 4 c of the second casing 4, but that the protrusion 3 c protrudes from the side wall 4 c of the second casing 4 so as to come into contact with the side wall of the first casing 3.

Furthermore, instead of the protrusion 3 c, a protrusion electrically connected to a back face of a top plate of the second casing 4 may be provided in an upper end face of the side wall of the first casing 3 to which the optical pickup part 8 a makes a closest approach. That is, at a portion between the first casing 3 and the second casing 4 where there may arise a gap due to the closest approach of the optical pickup part 8 a, a protrusion for maintaining electrical connection may be provided.

FIG. 6 is a perspective view showing a positional relationship between the first casing and the printed wiring substrate of the control circuit block. FIG. 7 is a perspective view showing a state in which the printed wiring substrate is excluded in FIG. 6. FIG. 8 is a schematic sectional view showing a structure of an interfacing connector portion in the control circuit block.

As shown in FIGS. 6, 7 and 8, at a portion of the bottom of the first casing 3 corresponding to the connector 11 b mounted on the printed wiring substrate 10, an opening 3 d for allowing the connector 11 b to be protruded outward of the first casing 3 is provided. A flat cable 12, which is a cable for external connection to fulfill transmission and reception of signals to and from external electronic equipment (not shown), is inserted into the connector 11 b protruding from the opening 3 d.

Also, the opening 3 d of the first casing 3 is formed at a bottom portion of a recess portion 3 e recessed from outside to inside of the first casing 3. The recess portion 3 e is so sized as to accommodate the connector 11 b protruding from the opening 3 d so that the connector 11 b is prevented from extending beyond the bottom face of the first casing 3.

Further, a surface 3 f which is a portion of the recess portion 3 e for accommodating the connector 11 b therein and along which the flat cable 12 inserted into the connector 11 b extends is formed as a sloped surface sloped from the bottom portion of the recess portion 3 e toward an outer surface of the first casing 3. By laying down the flat cable 12 along the sloped surface 3 f so that the flat cable 12 is inserted into the connector 11 b protruding from the opening 3 d, the flat cable 12 can easily be electrically connected to the connector 11 b. For practical implementation of this, the connector 11 b has an insertion opening into which the flat cable 12 is inserted in a direction crossing with, preferably orthogonal to, the direction in which the connector 11 b protrudes from the opening 3 d.

According to such an interconnection structure around the connector 11 b as shown above, the flat cable 12 can be provided so as to extend from the connector 11 b while kept along the first casing 3, which is an electric conductor. In this case, a loop area over which a common mode current flows in the flat cable 12 can be reduced. As a result, radiation noise generated from the flat cable 12 can be reduced, so that radiation noise generated from the optical disc drive device can be reduced.

Further, since the opening 3 d that allows the connector 11 b to be protruded is formed at a bottom portion of the recess portion 3 e recessed inward of the first casing 3, the connector 11 b can be placed so as not to extend beyond the bottom face of the first casing 3.

In this embodiment, the opening 3 d of the first casing 3 is formed at a bottom portion of the recess portion 3 e. However, the present disclosure is not limited to this. For example, the opening 3 d that allows the connector 11 b of the printed wiring substrate 10 to be protruded outward may be formed in the first casing 3 without forming the recess portion 3 e.

Further, the external connection cable connected to the connector 11 b and laid down along the sloped surface 3 f of the recess portion 3 e of the first casing 3 is not limited to the flat cable 12.

As described above and as shown in FIG. 8, the printed wiring substrate 10 is screwed to the fitting portions 3 b of the first casing 3 with screws 13. More specifically, the printed wiring substrate 10 is fixed to the first casing 3 in a state that the ground pattern 10 a formed around the connector 11 b is in electrical contact with the fringe portion of the opening 3 d of the first casing 3.

FIG. 9 is a schematic view showing a contact state between the fringe portion of the opening 3 d of the first casing 3 and the ground pattern 10 a of the printed wiring substrate 10. As shown in FIG. 9, the ground pattern 10 a of the printed wiring substrate 10 is fixed to the fitting portions 3 b of the first casing 3 with the screws 13, and thereby maintained in a state of electrical contact with the bottom portion (a portion indicated by area A) of the recess portion 3 e, which is a fringe portion of the opening 3 d of the first casing 3.

According to such an interconnection structure around the connector 11 b as shown above, the ground pattern 10 a of the printed wiring substrate 10 is securely electrically connected to the exterior casing 1. Also, the ground pattern 10 a of the printed wiring substrate 10 is formed so as to surround the periphery of the connector 11 b, coming into electrical contact with the first casing 3. Therefore, release of radiation noise to the outside through between the connector 11 b and the opening 3 d can be reduced. That is, the connector 11 b is protruded from the opening 3 d in a state that shielding is provided between the connector 11 b and the opening 3 d. In addition to this, intrusion of foreign matters into the exterior casing 1 through between the connector 11 b and the opening 3 d can be suppressed.

As described hereinabove, according to this embodiment, in the optical disc drive device, radiation noise to the outside can be reduced. Further, by virtue of the structure in which radiation noise is structurally reduced, there can be provided an optical disc drive device showing less variations in the radiation noise reduction effect.

Although the present disclosure has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such Changes and modifications are to be understood as included within the scope of the present disclosures as defined by the appended claims unless they depart therefrom. 

1. An optical disc driving device having: a metallic exterior casing composed of a first casing and a second casing; and an internal unit to be housed in the exterior casing, the internal unit including an optical pickup unit having an optical pickup part that moves in radial directions of an optical disc to perform recording or reproduction of information signals on the optical disc, wherein at a portion, which the optical pickup part moved radially outward of the optical disc makes a closest approach to, in either one of the first casing or the second casing. opposed to the first casing, a protrusion for electrically connecting the first casing and the second casing to each other is provided.
 2. The optical disc driving device according to claim 1, wherein the first casing is box-shaped, the second casing is such lid-shaped as to be engageable with the first casing, and the protrusion is provided at the portion opposed to a disc insertion opening, which an optical disc is to be inserted into, in either one of a side wall of the first casing or a side wall of the second casing.
 3. The optical disc driving device according to claim 2, wherein the exterior casing is so made up that the internal unit is housed therein by hooking and temporarily fixing a front portion of the second casing on one side closer to the disc insertion opening to a front portion of the first casing, laying a rear portion of the second casing on a rear portion of the first casing, and screwing the rear portion of the second casing to the rear portion of the first casing with a screw.
 4. The optical disc driving device according to claim 3, wherein the rear portion of the second casing and the rear portion of the first casing are screwed with two screws, and the protrusion is provided at either one of the side wall of the first casing or the side wall of the second casing corresponding to an intermediate position of the two screws. 